1st Congress
- 1st Congress of the Comintern
- 1st Congress of the Commonwealth of the Philippines
- 1st Congress of the Indonesian Democratic Party
- 1st Congress of the National Christian Party
- 1st Congress of the Philippines
- 1st Congress of the Russian Social Democratic Labour Party
- 1st Congress of the Workers' Party of North Korea
- 1st National Congress of the Chinese Communist Party
- 1st National Congress of the Kuomintang
- 1st National Congress of the Lao People's Party
- 1st National People's Congress
- 1st Otan Founding Congress
- 1st United States Congress
- 2nd Congress (disambiguation)
- 3rd Congress (disambiguation)
- 4th Congress (disambiguation)
- First Continental Congress
- First European congress of astronomers
- First International Statistical Congress
- First International Syndicalist Congress
- Geneva Congress (1866)
- International Congress of Physics
- International Workers Congresses of Paris, 1889